1. Field of the Invention
This invention relates to piezoelectrically actuated vibratory type liquid atomization devices and more particularly it relates to novel structures for such devices which are characterized by low liquid loss and high efficiency handling of liquids being atomized.
2. Description of the Related Art
U.S. Pat. No. 5,758,637 to Ivri et al. shows a liquid dispensing apparatus in which a cantilever beam is attached to an electronic circuit and which bends and vibrates in response to actuation of a piezoelectric element attached to the beam. The vibration of the beam is transferred to a shell member to produce atomization of liquid supplied to the shell member. U.S. Pat. No. 5,297,734 also shows a bendable cantilever beam of piezoelectric material which is attached to an atomization plate.
U.S. Pat. No. 4,119,096 to Drews shows a medical inhaler in which a transducer is mounted in cantilever fashion within the inhaler. U.S. Pat. No. 5,283,496 to Hayashi et al. shows a crystal resonator which is held by supporting wires of electrically conductive material and which press on the sides of the resonator. U.S. Pat. No. 4,087,495 to Umehara show an ultrasonic air humidifying device in which an ultrasonic vibrator assembly is held in place by a pair of stays. U.S. Pat. No. 4,911,866 shows a fog producing apparatus that is suspended within a liquid bath by means of carrier members extending from a float.
U.S. Pat. No. 5,657,926 to Toda shows an ultrasonic atomizing device in which a piezoelectric vibrator and a vibrating plate are held between supporting elements and an adjacent end of a liquid keeping material which extends out of a liquid bath.
U.S. Pat. No. 5,021,701 to Takahashi et al. shows a piezoelectric vibrator mounting system for a nebulizer, wherein a piezoelectric actuator is energized via spring loaded electrodes which press on the sides of the actuator.
U.S. Pat. No. 4,301,093 to Eck and U.S. Pat. No. 5,518,179 to Humberstone et al., as well as European Patent Publication EPO 897 755 A2 to Satoshi Yamazaki et al. show wick arrangements extending from liquid reservoirs to atomization plates which are vibrated by piezoelectric actuators.
U.S. Pat. No. 5,152,456 to Ross et al., U.S. Pat. No. 5,823,428 to Humberstone et al., U.S. Pat. No. 6,014,970 to Ivri et al. and U.S. Pat. No. 6,205,999 to Ivri et al. show various means for supporting a piezoelectric actuator and an atomization plate.
U.S. Pat. No. 4,479,609 to Maeda et al. shows a felt wick core which is enclosed by and which extends out from the ends of protective plates. However, the wick is neither solid nor dimensionally stable.
None of the foregoing patents address the problem that one encounters upon atomizing liquids which are characterized by low viscosity and low surface tension which are common among fragrances, air fresheners and insecticides. These liquids tend to migrate along the structural elements of the atomizer device and cause wetting of its various surfaces. As a result it becomes difficult to handle the atomization device. Further, its performance deteriorates and valuable liquid is lost without being atomized.
Further, none of the above patents discloses any arrangement to ensure that liquid is supplied to a vibrating plate from a fixed location relative to the plate in order to provide a sufficient supply of liquid without appreciably damping the vibrations of the plate.
Finally, the prior art fails to disclose any arrangements for efficiently holding a vibrating atomization plate and actuator element in a liquid atomization device.